1. Technical Field
The disclosure relates to a light sensing device. More particularly, the disclosure relates to a light sensing device having a metal oxide semiconductor layer.
2. Description of Related Art
Light sensors can be widely applied in image products, such as security monitoring, digital camera, toys, personal digital assistant (PDA), image phones, fingerprint identifiers etc. Light sensors can be divided into ultraviolet light sensors, visible light sensors, and infrared light sensors. The light sensitive materials of these light sensors are made from different materials.
For ultraviolet light sensors, groups III and V metal nitrides, such as gallium nitride (GaN) or aluminum gallium nitride (AlGaN), are usually used to be ultraviolet light sensing materials. However, the formation process of GaN and AlGaN is highly polluted and hardly integrated into the existed semiconductor processes. Therefore, the applicability of the groups III and V metal nitrides is lower.
For visible light sensors, amorphous silicon or polysilicon are usually used to be the light sensitive material. However, the stability of the visible light sensors using the amorphous silicon or polysilicon as the light sensitive material is poor. Therefore, the amorphous silicon or polysilicon cannot be effectively applied on products containing light sensors.
Furthermore, if a light sensing device has to integrate the ultraviolet sensors and the visible light sensors above, the complexity of the integrated fabricating process will be increased since the light sensitive materials of the ultraviolet sensors and the visible light sensors are different. Therefore, the production cost will be increased, and the light sensing device is thus not suitably mass-produced.